Player: I move to the bodies and look at them, but not touching, in case they are contagious. What did they die of?
I see a problem here. What happens if the player with a +12 "Medicine" skill says "I go over to the bodies and try to find out how they died."
Without the "but not touching", do you assume this person highly skilled in Medicine touches the possibly diseased bodies?
Clearly they failed to be cautious of the possibility of disease and now must make a Con save.
Imagine this in combat:
I swing my sword at the foe!
Well, a competent swordsman would actually approach, attempt to bait a foe into making an opening, then exploit that opening. The above character just ran up and left themselves open!
Clearly the foe stabs them and kills them before their blow lands.
Me: You'll need to get closer to see anything. Are you moving or touching the bodies, or just looking at them? How close are you getting?
This can easily read like "please list the ways I can screw you over if you do something that could cause problems".
When someone says "I use skill X", treat it as "I want to engage my characters expertise at X to determine what I should do or what I can know from what I see".
Me: You see a pile of bodies at the end of the field.
Player: I roll Medicine. I get a 32.
Me: They appear to be dead, but it is hard to tell from here. But if they are diseased, you don't want to touch them; it could be plague.
You provided stimulus; the bodies. They asked to use their skills. Lacking an action backing up the skills, this is a knowledge-type check.
If they roll well, you give them good advice for this general situation based off that kind of knowledge.
Now they say "I want to know how they died", they have already made a medicine knowledge roll. You can say "you cannot tell from this far away".
To directly address the issue, when someone says "I roll Medicine", tell them "you cannot roll a skill without saying how or why you are using it". If it continues, add "please stop simply invoking the names of skills." If it continues, talk about hard consequences "if you simply roll a skill without saying why or what you are trying to do, you are now going to be spending the next 10 to 60 minutes reminising and rambling on about your training in that skill unless something urgent comes up and the situation changes".
This is direct communication. No back and forth. You start with "that won't work". You then ask them to stop doing the thing that won't work. You then outline consequences, and deliver.
Note that the rambling bit is "until the situation changes". Basically it is now up to the rest of the party to cause the situation to change; if someone else moves towards the corpses or does an action, this gives the "I roll medicine" person back their "turn". Meanwhile, they are rambling about medical training:
Why, I remember when I was a wee lad and I had to deal with a corpse pile much like that. Oh boy did it stink. To high heaven. Pee-yew. Not as stinky as the time I had to cut open a cow to get a calf out. We penetrated to bowels, and it got all over everything, even my lunch. Had to clean it off before I could eat it...
Next, when you actually get them to do things, don't play genie. They don't touch dangerous corpses without first making a medicine check to know not to do it (or anything appropriate), even if they said they would or you imply they would from what they describe they do.
Yes, this means that the pitch black hole in the statue's mouth containing the globe of annihilation doesn't get touched unless they first fail a knowledge(arcana) check.
These are all sticks. When a player actually does describe in reasonable detail how to go about doing something, give out advantage. Like candy. Provide a carrot to go along with the stick.
Stick: a roll without action is merely a knowledge check. It gives a clue asto what to do, it doesn't do anything. Eventually it even wastes time (you "lose your turn"), or forces disadvantage on the knowledge check ("Next time be more specific. No, you cannot reroll").
Carrot: describing actions more than typical grants advantage on the check like candy.